Brahidactyly is an underdevelopment of the phalanges, manifested in the shortening of the fingers on the feet and hands, resulting from a genetically determined defect transmitted by inheritance. Manifestations of this anomaly is the decrease in the length of the feet and hands, short-fingered, hypoplastic nail plates, and in some cases, syndactyly . As diagnostic measures, DNA diagnostics and ray methods of bone visualization are at the forefront, and as an effective therapeutic measure, only a surgical method of eliminating a defect should be considered. It should be borne in mind that the emergence of brachydactyly is possible not only with a decrease in the size of individual phalanges, but also due to their complete absence.
The causes of brachidactyly
This pathology is characterized by a rather high incidence rate in the overall structure of genetic developmental defects, and this fact is explained by the dominant type of transmission of the defective gene, i.e. for the development of a child, brahidactyly enough that one of the parents was the carrier of the defective gene. The incidence of brachidactyly in the general structure of hereditary anomalies of the hands and feet is about 24%.
In the era of development of diagnostic technologies, as well as genetic engineering methods, conditions for early prenatal diagnosis of brachidactyly are created by the method of triplex three-dimensional ultrasound examination during pregnancy.
Preparations for the use of etiotropic empirical treatment have not yet been developed, but a large number of scientific studies on this issue are currently under way. Medico-genetic counseling of the family, which consists of at least one member suffering from this type of anomaly, provides an obligatory warning to the geneticist about the risk of having a baby with brachidactyly. The category of people who are subject to genetic counseling is primarily parents who have a baby with brachydactyly, both people who want to start a family with a patient with brachidactyly, and families whose parents suffer from this anomaly.
Symptoms of brachidactyly
In a situation where brachydactyly is an isolated developmental disorder, the clinical manifestations of the child will be minimal, and it should be treated as an exclusively cosmetic defect. However, it should be borne in mind that in most cases this pathology acts as a syndrome and is a manifestation of more gross congenital genetic diseases.
The most common congenital pathology, in which brachydactyly develops on a par with other vices, is Down's syndrome . With this hereditary anomaly, in addition to brachidactyly, the child displays other phenotypic signs (epicanthus, brachycephalic type of skull, funnel-shaped chest, shortening of the neck).
Brahidactyly with Poland syndrome is combined with amyastia and rib deformation, and in the case of Aarski-Scott disease, the child concurrently with short-haired features of symptoms of phimosis, mental retardation and instability of the joints.
In a situation where brachodactyly in a child is combined with the presence of atresia of the khohan, hypoplasia of the frontal sinuses, short stature and signs of secondary hypothyroidism , and in some cases, oligophrenia , the patient should have a syndrome of the median cleft of the facial skull.
If the child has brahidactyly without evidence of adhesion to phalanges or polydactyly , then in most cases this anomaly does not restrict the function of the hand or foot. With more pronounced malformations of phalanges, there may be a disruption in the function of interphalangeal, metatarsophalangeal joints, which greatly complicates the supporting and motor function. In addition, in most cases, brahidactyly is combined with a dysplastic lesion of the nail plate of the affected finger, which has a non-aesthetic appearance and needs correction. The shortened fingers have an unusual configuration, due to some flattening and splitting of phalanges.
It is necessary to distinguish such special variants of brachydactyly as ectrodactyly, in which there is a deficiency of extremely distal phalanges with the preservation of the normal bone structure of metacarpal bones, as well as adctyly, which is the most severe form of short-fingeredness, since in this pathology the shortening of the hand develops as a result of complete absence of one or several phalanges.
Types of brachidactyly
To distinguish all variants of bone anomalies phalanges, in traumatological and orthopedic circles it is customary to classify brachydactyly according to clinical types.
Brahidactyly A is accompanied by shortening of the middle finger, deviation of the phalanges, and dysplastic changes in the nail plates. These changes can occur in different severity variants, therefore it is common to divide type A brachidactyly into five clinical variants.
The type of Farabi, or type A1, implies changes in all phalanges of the middle finger as a rudimentary structure in combination with shortening of the proximal phalanx of the thumbs of the feet and brushes, as well as a general growth retardation.
Type Mora Brita, or type A2 is manifested by the presence of all phalanges of the middle finger of the brushes, but their significant shortening. A remarkable fact is the preservation of the normal development of the remaining phalanges on hands and feet. In addition to shortening the phalanx of the middle finger, the shape of the phalange of the middle finger changes toward a rhomboid shape with concomitant radial deviation. A variant of this type is brachidactyly, combined with the clinodictyly of the fifth finger.
The clinodactyly of the fifth finger, or type A3, consists in shortening and radial deviation of the exceptionally medium phalanx of the fifth finger on both hands.
With type Temtami, or type A4, shortening of the second and fifth fingers of both hands is observed due to underdevelopment of the middle phalanx. With the localization of pathological changes on the feet, there are valgus-heel clubfoot.
Type A5 is accompanied by a pronounced shortening of the second and fifth fingers on the hands, due to the complete absence of the middle phalanx in combination with dysplasia of the nail phalanges.
The principal difference between brachidactyly of type B is that the child has an anomaly of development of nail phalanges with concomitant syndactyly of the second and third finger. A typical for this variant of brachydactyly is the simultaneous damage of the hands and feet. The above changes are accompanied by anomalies in the development of bone tissue of the spine, skull and teeth.
Brachydactyly type C is a serious congenital pathology, in which, in addition to shortening of the proximal phalanges, there is a lack of development of metacarpal bones, as well as fusion of phalanges with each other. Children suffering from this pathology are characterized by short stature, and in some cases even mental retardation.
Brachydactyly type D has the second name "brachodactyly of the thumb" and is the most common anomaly in the development of phalanal bones. It is noteworthy that this type of underdevelopment of phalanges of the first finger is observed equally often both on the upper and lower extremities.
Type E is a rare pathology, in which the shortening of the hand or foot does not develop as a result of the bony defect of phalanges, but as a consequence of the isolated underdevelopment of metacarpal bones. In addition, the phenotypic manifestations of this anomaly is a symmetrical underdevelopment of the clavicles.
Treatment of brachydactyly
Due to the fact that brachodactyly is an abnormality of the development of bone tissue with a typical localization in the projection of phalanges of brushes and feet, the only effective method of correcting these changes is surgical. Conservative techniques that involve the use of physiotherapeutic manipulations should be considered as additional therapeutic measures in the postoperative period, as well as preventive measures in preventing the development of secondary deforming arthrosis of small joints of the feet and hands.
Surgical techniques allow not only to eliminate the existing interphalangeal fusion, but also to increase the linear dimensions of the brushes and feet. As an operational aid for lengthening the size of the hand or foot, autotransplantation, pollicization and distraction are used. When eliminating interphalangeal fusion, not only bone, but also tendon-muscle, as well as skin plastic is performed.
The use of surgical treatment with brachidactyly is acceptable only for the purpose of eliminating the violations of the motor function of the extremities and, to a lesser extent, to eliminate the cosmetic defect.